Download classifying stars

Name: ____________________________________________ period: ___________ date: _______________
Classifying Stars
Stars can be classified according to three characteristics: size, temperature, and brightness.
Size
When talking about a star’s size, astronomers rank them from largest to smallest... Here is how they are
arranged, the numbers refer to the diagram below:
5 * Supergiant (largest, 1000 times the diameter of the sun)
4 * Giant (10-100 times the diameter of the sun)
3 * Medium Sized (like our sun which is 109 times the diameter of earth, or 1,392,000 km)
2 * Dwarfs (white dwarfs, which can be smaller than earth)
1 * Neutron stars (average to be ~16 km in diameter--maybe the distance you came to school)
Temperature
Astronomers have created a chart that can describe the surface temperature of stars. The temperatures
correspond to colors. Scientists can study the color of stars to determine how hot the surface temperature is
on the stars. They have determined that the hottest stars burn about 50,000˚C or 28,000˚F on stars that are a
white-blue color, and the coolest stars are about 3,000˚C or 1,600˚F on stars that are reddish in color. The
chart below shows how stars between these two extremes are classified:
Color
Average Surface Temperature (˚C)
Blue to Blue-white
35,000 +
White
10,000
Yellow
6,000
Red-Orange
5,000
Red
3,000
Brightness
The brightness of a star depends on its size, temperature and distance from the earth. Some stars appear
brighter to us on earth because they are much closer than others, astronomers call this apparent magnitude
(HOW BRIGHT A STAR APPEARS.) However, if astronomers could take two stars and place them exactly
the same distance from earth, they could tell which one really is brighter... unfortunately, this is not possible,
but astronomers can measure the amount of light a star actually gives off. This is called its absolute
magnitude (HOW BRIGHT A STAR REALLY IS), and it is this measurement that scientists use more often
to classify stars.
There are several stars that scientists have classified according to the three characteristics described on the
front. Here is a list of the stars, their absolute magnitude and their surface temperature/color description.
Use this information and plot points on the chart below that represents each star, make sure to label each
point with the name of the star. Eventually, we will use this to also show how these stars can be grouped
according to their size
Alcor (white, middle brightness)
Algol (blue-white, middle-high brightness)
Alpha Centuri B (red-orange, middle-low brightness)
Antares (red, high brightness)
Barnard’s Star (red, low brightness)
Canopus (yellow, midle-high brightness)
Deneb (white, high brightness) Mira (red, middle-high brightness) Procyon (yellow, middle brightness)
Polaris (yellow, high brightness) Regulus (blue-white, middle-high brightness)
Sirius (white, middle brightness)
Spica (blue-white, middle-high brightness)
Tau Ceti (yellow, middle-low brightness)
Vega (white, middle-high brightness) Blue-white
White
Aldebaran (red-orange, middle-high brightness)
Alpha Centuri A (yellow, middle brightness)
Altair (white, middle brightness)
Arcturus (red-orange, middle-high brightness)
Betelgeuse (red, high brightness)
Capella (yellow, middle-high brightness)
Epsilon Eridani (red-orange, middle-low brightness)
Mizar (white, middle-high brightness)
Procyon B (yellow, low brightness)
Pollux (red-orange, middle-high brightness)
Rigel (blue-white, high brightness)
Sirius B (white, middle-low brightness)
Sun (yellow, middle brightness)
Van Maanen’s Star (yellow, low brightness)
Zeta Eridani (blue-white, high brightness)
Yellow
Brightness
High
Low
Average Surface Temperature
Red-orange
Red